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RECEIVE DROPS ON BOTH SETUPS

Sonar

Sr. Member
Apr 8, 2016
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I've heard of this happening to others, but never inquired to why..
I'm trying to get my station setup working as good as it could with my unfortunate antenna situation.
My IMAX 2000 is about 10 feet from ground to feed point.
If the antennas gonna go higher it won't be by much. About another 5 feet, and that's it.
Back to the issue at hand. As I change my channel from 1 to 40 my receive increases. Then drops down once I reach channel 1. It begins to rise as I go higher in frequency.
Switching from channel 40 to 1 will cause the receive to drop by at least one s unit.
I had a local give me a five count on channel 40.
His signal was an S9.
One click puts my Sonar on channel 1 where his signal is now an S8 (slightly less.)
As I change the channels one by one higher I can actually hear the normal everyday static getting louder as the noise level visual gets higher on the S unit meter.
This also happens with my Uniden Madison. Telling me it's most likely not the rigs.
Is there a simple fix for this issue? And how common is it?
It would be nice to have both transceivers receive on all channels as they do on channel 40.
This happens weather on SSB or AM.
I want to add that I do have a Dawia 2 position antenna switch, an amp (one for the Sonar, one for the Madison) and an swr/power meter in line.
Why does this happen?
And how can it be rectified?
 
Last edited:

sp5it means align the receivers for more equal sensitivity across the band,

simple test, stick a short piece of wire in the antenna socket & rock between ch1 / ch40 listening to the noise,
is there still a notable change in noise level.
 
OR whoever you are having help you test your receive radio is mis aligned.
His transmitter puts out more wattage on one side of the band than the other, thus your receive reflects the strength of his transmitted signal.
Compare other signals to see how the receivers are doing.

Also any switches you may have in line may be attenuating the signal.
try antenna straight to your radio nothing in between see if results vary.
 
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OR whoever you are having help you test your receive radio is mis aligned.
His transmitter puts out more wattage on one side of the band than the other, thus your receive reflects the strength of his transmitted signal.
Compare other signals to see how the receivers are doing.

Also any switches you may have in line may be attenuating the signal.
try antenna straight to your radio nothing in between see if results vary.
That would be the easiest thing for me to do. I will remove the jumper from each rig and install the antennas coax directly into the rigs so239. I will report the results. And depending on those results you might be able to help me figure out how to rectify the problem. The lack of antenna height already affects my receive adversely. I would like to receive as strong on every channels as I do on 40. Thank you.
 
It could be as simple as just more noise on diferent parts of the band. Yesterday i was on 75 meters in a section i'm not normally in and the noise was S1 and i was like YES then scrolled up the band and i had S4 noise :( which still was good LOL.
 
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It could be as simple as just more noise on diferent parts of the band. Yesterday i was on 75 meters in a section i'm not normally in and the noise was S1 and i was like YES then scrolled up the band and i had S4 noise :( which still was good LOL.
It could be an antenna problem.
If you have used a manual antenna tuner you know as you approach resonance the noise level goes up. I think one of my manuals says to "Tune for the most noise." And that does work. You can get in pretty close without keying up the transmitter. I keep a log of all of my tuner settings so I can tell right off if there is something amiss with the antennas. My IC-7100 does not have the auto tuner and that is my favorite radio for mobile use in spite of all of the wires.
 
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It could be as simple as just more noise on diferent parts of the band. Yesterday i was on 75 meters in a section i'm not normally in and the noise was S1 and i was like YES then scrolled up the band and i had S4 noise :( which still was good LOL.
No. Definitely an issue. As I go from the lower frequencies to the higher the receive obviously gets stronger. It doesn't change from day to day, but is constant. Thanks for replying. Any advice will eventually get it straightened out.
 
It could be an antenna problem.
If you have used a manual antenna tuner you know as you approach resonance the noise level goes up. I think one of my manuals says to "Tune for the most noise." And that does work. You can get in pretty close without keying up the transmitter. I keep a log of all of my tuner settings so I can tell right off if there is something amiss with the antennas. My IC-7100 does not have the auto tuner and that is my favorite radio for mobile use in spite of all of the wires.
No antenna tuner here. Here, Sonar 2340 and madison. So obviously no internal AT. And I don't know if an external one is something that can be used. Even if that's an option I don't think I want to be fussing with that. Here in NJ we had a foot of snow with temps in the single digits.
I'm beginning to notice other issues.
For one, when I turn on either the Sonar or madison (and the amps that I drive with them) the SWR on my initial key is above 2.
I found that keeping the either station keyed for about 3 seconds starts a process to to where the SWR begins to drop where it eventually reaches it's 1:3.1 where it normally sits. During and after the storm and single digit temps my swr was above 3, and didn't drop until the temps went above freezing. I think my antenna was ireversably damaged.
I will eventually get someone to make sure that the so239 on the IMAX 2000 is dry (no moisture or water inside) and tight.
After that if the problem continues the easiest thing for me to do is just to purchase a new IMAX 2000. I believe your assessment of an antenna issue is correct. I just wanted to add that my disability makes it imposable for me to do little to no diagnosis, and getting a friend to install a new imax would be the easiest option for me. Thanks. 73's
 
I think you might have a moisture problem either in the coax or the antenna. The antenna tuner would work but that is just hiding a problem and not the answer.
 
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